Skills: Perception +14, Stealth +11
Saving Throws: STR +18, DEX +12, CON +18, WIS +15
Damage Resistances: Acid, Fire, Cold, Lightning
Damage Immunities: force, psychic, Poison, Bludgeoning, Piercing, and Slashing from Nonmagical Attacks
Condition Immunities: Charmed, Frightened, Poisoned
Senses: Blindsight 120 ft., Passive Perception 24
Languages: Understands Abyssal, Draconic, and Primordial but can't speak
Challenge: 27 (105,000 XP)
Ghostly Mountainous Presence: The Mountain Worm Revenant can occupy the same space as other creatures and terrain, which is treated as difficult terrain.
True Poison: All poison damage dealt by this creature treats immunity as resistance and bypasses resistance completely.
Magic Resistance: The Mountain Worm Revenant has advantage on saving throws against spells and other magical effects.
feature: percieves time as if it was very slowe down, + 20 initiative and as one reaction per turn.
feature: 3 times per day the worm can as a reaction choose to revert the results of a offensive roll torwards itself, for exmaple conerting a critical hit into a cirirtical fail and making the attack miss. This is only for roll made by other creatures than the worm itself.
Undying Vengeance: If it dies, the corpse regains 50% of its HP and an additional 50% as temporary hit points. Its intelligence drops to one, and it attacks whatever killed it, then any other targets, dying after 1 hour regardless of its current HP.